What is the latest classification of hypertension in pregnancy?

Latest Classification of Hypertension in Pregnancy

According to the 2018 International Society for the Study of Hypertension in Pregnancy (ISSHP) classification, hypertensive disorders in pregnancy are categorized into hypertension known before pregnancy or present in the first 20 weeks (chronic hypertension, white-coat hypertension, masked hypertension) and hypertension arising de novo at or after 20 weeks (transient gestational hypertension, gestational hypertension, and preeclampsia de novo or superimposed on chronic hypertension). 1

Classification Framework

Hypertension Known Before Pregnancy or Present in First 20 Weeks:

• Chronic hypertension - Can be essential or secondary 1
• White-coat hypertension - Elevated clinic BP but normal home or ambulatory BP 1
• Masked hypertension - Normal clinic BP but elevated BP at other times 1

Hypertension Arising De Novo At or After 20 Weeks:

• Transient gestational hypertension - Hypertension that resolves without treatment during pregnancy 1
• Gestational hypertension - Persistent hypertension without features of preeclampsia 1
• Preeclampsia - Gestational hypertension with one or more features of maternal organ dysfunction 1
  • Can occur de novo or superimposed on chronic hypertension 1

Important Diagnostic Criteria

• Hypertension definition: Systolic BP ≥140 mmHg and/or diastolic BP ≥90 mmHg 1
• Severe hypertension: Systolic BP ≥160 mmHg and/or diastolic BP ≥110 mmHg 1, 2
• Confirmation requirements:
  • For severe hypertension: Confirm within 15 minutes 1
  • For less severe hypertension: Repeated readings over several hours 1

Preeclampsia Diagnostic Features

Preeclampsia is diagnosed when gestational hypertension is accompanied by ≥1 of the following new-onset conditions at or after 20 weeks' gestation:

• Proteinuria 1
• Other maternal organ dysfunction, including:
  • Renal insufficiency
  • Liver involvement
  • Neurological complications
  • Hematological complications
  • Uteroplacental dysfunction 1

Important Clinical Notes

• The term "severe preeclampsia" is no longer recommended in clinical practice; instead, preeclampsia should be described as with or without severe features 1
• HELLP syndrome (hemolysis, elevated liver enzymes, low platelets) is considered part of the preeclampsia spectrum, not a separate disorder 1, 3
• Transient gestational hypertension carries a 40% risk of developing gestational hypertension or preeclampsia later in pregnancy 1
• When a woman presents with hypertension at or after 20 weeks with unknown earlier BP, she should be managed as if she has gestational hypertension or preeclampsia 1
• Proteinuria is present in approximately 75% of preeclampsia cases but is not required for diagnosis 1

Monitoring Recommendations

• All women with chronic hypertension should have baseline tests (complete blood count, liver enzymes, renal function, uric acid, and proteinuria assessment) to help detect superimposed preeclampsia later in pregnancy 1
• Ambulatory blood pressure monitoring may help predict progression from gestational hypertension to preeclampsia 4
• Women with transient gestational hypertension should receive extra monitoring throughout pregnancy, ideally including home BP measurements 1

This classification system provides a clear framework for diagnosing and managing hypertensive disorders in pregnancy, which affect 6-10% of pregnancies and represent a significant cause of maternal and fetal morbidity and mortality 4, 5.